Energizer 2500 maH

jeffb

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Last year I purchased a 15 min Energizer charger and 20 Energizer 2500 maH batteries. Sometimes charged in 15 min charger, sometimes in BC-900 at low charging rate. (less than 10-12 charges on ea 4)

Upon receiving new Maha C-9000, used "break in" to form several sets, along with some new Powerex 2500's that I had on the shelf.

After seeing poor readings, just did a "discharge" and (4) tested in the 1800's capacity.

I recall reading about "issues" with these batteries and have noticed, that the external flash on my digital camera was performing extremely poorly even with these newly charged Energizeres.

My inclination is to get rid of all these and use the existing Powerex and some new Eneloops purchased (may purchase more eneloops,as somtimes they sit for a few weeks before use.)

I read several comments about these batteries recently and have "searched" unsuccesfully............so any comments would be appreciated.

Many Thanks,

jeffb
 

Aaron1100us

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I've used the energizer 2500's in my mag 85 since last spring without any problems. I charge them with my 15 minute energizer charger every time and get about 45 minutes runt time. I have had two cells go bad on me but I figured that wasn't too bad.
 

Carbo

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Just yesterday I disposed of 8 Energizer 2500's. Their performance deteriorated so badly I couldn't use them any longer. They would be completely discharged three days after being fully charged. So whenever I would need them in my digital camera, they were useless. That, and two days run time in my wireless mouse made me realize we needed to part company.
I treated myself to a dozen Eneloops as a replacement, based on all the things I have read about them, along with my usage patterns and needs. I think, for me at least, this is the way to go.
 

not2bright

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I have been using a set of Energizer "HR" stamped 2500's for some time in a pair of L1Ps and my workout MP3 player.

I just ran them through a "Refresh Analyze" cycle and got:

2335

2331

2342

2346

These are ~100 mAh lower than my Sanyo branded 2500s but seem pretty good.
 

ikendu

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I have 8 Energizer 2500s that I am about ready to pitch. Within a few days of charging, they are essentially dead. My older Energizer 1850s will sit for weeks and still retain useful charge. I've basically stopped using the 2500s and only use the older 1850s now.

Are all high capacity NiMHs as bad as these Energizer 2500s? If so, it looks to me like the NiMH manufacturers are ruining the reputation of NiMHs with these new but unworkable high capacity AAs. For the moment, when people ask me, I only recommend the Eneloop brand of NiMHs.
 

bob_ninja

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The general consensus seems to be that E2500s are not suitable for high current applications. That is why you'll see perfectly fine perfromance in low current apps (such as wireless mice and MP3 gadgets) while high current usage ruins them quickly.

My guess is that your flash draws a lot of current, hence E2500s are not suitable. You could use any 2000 or lower capacity batteries. Eneloops appear to be very robust and possibly the best choice.

In any case, make sure to use E2500s only for low current gadgets.
 

Mike abcd

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Lots of us have had problems with the Energizer 2500 NiMH AA cells developing extremely high self discharge. I've had 6 out of 24 (25%) go bad.

If you contact Energizer, they will send you a postage paid label to return them, and according to posts from other folks, then send you a coupon for the retail value of the cells returned that's good on purchasing more.

I've got the mailing label but haven't got around to sending mine back yet.

Mike
 

jeffb

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Thanks All,
ordered Eneloops for new Maxlite "naked" (coming soon), other AA lights and
Camera accessories!!

jeffb
 

Trouthead

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Just ran my Energizers through a "refresh analyze" cycle on the MAHA C-9000. They previously had been charged a few times on the Energizer charger that came with the batteries (Sam's Club).

I got the following 2297, 2311, 2312, and 2298. Is this good or bad?
 
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BentHeadTX

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All my "HR" 2500mAH batteries are dying off

Sony 2500 cells would die in a few days
Energizer 2500's would die in a week or so
Powerex are developing high discharge rates and severe voltage sag under loads exceeding 800mA.

I am using Powerex 2700's and they were great when they were new. Now, I have noticed the voltage is starting to sag a little under 1+ amp load although they don't have a major self-discharge problem. They will rotate into my 825mA draw 2AA lights and other various things.

Sooo, it is Eneloops for me and a few of those Titanium 1800mAH high discharge series AA cells to replace my current 2300 to 2500 cells. My best performing cells are Sanyo 1700mAH AA that are two years old. They will hold a charge for months in my 8AA Mag mod....

My Sanyo 1000mAH NiMH AAA cells are great though... but I don't trust them over time. The Eneloops will compliment those cells.

After messing with dozens of NiMH cells, it will be nice to have some that can handle 1 to 2 amp current draw, have low self-discharge and won't die in a week to two.
 

Curious_character

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not2bright said:
I have been using a set of Energizer "HR" stamped 2500's for some time in a pair of L1Ps and my workout MP3 player.

I just ran them through a "Refresh Analyze" cycle and got:

2335

2331

2342

2346

These are ~100 mAh lower than my Sanyo branded 2500s but seem pretty good.
I was puzzled by the relatively good capacities shown by the Maha at 500 mA discharge rate for some Energizer 2300s I have -- my own tests showed quite a bit less capacity at 500 mA discharge rate. I figured out the cause of the difference -- the Maha discharge current drops near the end of the discharge cycle. This squeezes more charge out of cells which have a high internal resistance -- which my Energizer cells did. After I discharged the cells to 1.0 volt at 500 mA (not with the Maha), I dropped the current to 100 mA -- and they ran for nearly 3 hours more until hitting 1.0 volt again! The total capacity was about what the Maha said, but it sure isn't what you'd get from the cells with a constant 500 mA discharge. So the Maha can be very optimistic about the capacity when the cells have a high internal resistance like my Energizer cells.

I'll make a more detailed posting about this before long.

c_c
 

SilverFox

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Hello Curious character,

I believe William stated that while the display shows the current dropping, it actually isn't... Something to do with the way the display receives its information vs the actual calculated information displayed at the end of the discharge cycle.

It will be interesting to see what you come up with. I assume you will be charging on the C9000 then utilizing something separate to discharge.

Tom
 

willchueh

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Discharge capacity is based on actual current integrated with respect to time. If the current drops, it is accounted for in the capacity.

William
 

CM

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I have 8 of these (they're actually made by Sanyo) from about the same vintage as yours and mine are still giving me very good to excellent performance. I do charge mine using a 1 hour charger for 1600mAH cells so they are not "fast charged" which I really think is the cause of the demise of many NiMH cells. I know they've made some improvements in technology but I think a 15 minute charge is excessive. Even if you charge them only "sometimes" in the fast charge mode. All it takes is a few hot charges and the cells will degrade rapidly.
 

LouRoy

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I had 4 of the Energizer 2500 that I used daily in a digital camera. I slow charged them on a charger than took 12 hours. They were never fast charged. After less than a year, the batteries would not hold a charge more than a few days. I threw them away and bought Eneloops.
 

Curious_character

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SilverFox said:
Hello Curious character,

I believe William stated that while the display shows the current dropping, it actually isn't... Something to do with the way the display receives its information vs the actual calculated information displayed at the end of the discharge cycle.

It will be interesting to see what you come up with. I assume you will be charging on the C9000 then utilizing something separate to discharge.

Tom
The current is actually dropping, according to William -- he said that the Maha current sink loses regulation below 0.9 volt. I don't know why it was designed that way -- it's not hard to do better. The one I designed long ago (20 years?) and have used for many years holds to well below that. (It's actually a constant current source, doing double duty as a discharge load.) But he's also confirmed that the capacity indication is based on the actual, rather than programmed, current, so at least it's honestly reporting the capacity, even if that capacity isn't being determined at the specified current drain.

Yes, I did my tests by first doing a refresh/analyze cycle with the C9000. After that was finished with the cell charged, I discharged it with a truly constant 500 mA current and got considerably less capacity than the Maha reported. The remaining reported capacity was reached by reducing the current to 100 mA. I tried a couple of other brand/type cells for comparison, and they didn't exhibit this characteristic.

The Maha-reported capacity would be reasonably representative of what you'd get in an unregulated light where the current drops dramatically as the cell approaches discharge. But you won't see the reported capacity in a regulated light if the cells have this characteristic.

I don't yet know how common the high resistance is, or if I just have some unusual cells. So far I'm seeing it in a set of four of the same type and age.

More later when I have a little more time.

c_c
 

willchueh

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Curious_character,

While it is not a instrument, the MH-C9000 can provide discharge current at 1-2% within set value.

As indicated in my earlier post, the MH-C9000 uses a two-point method for charging and voltage measurement. Therefore, to avoid contact resistance loss, the charger needs to pause the current and measure the voltage (also to eliminates noise from high current).

We call this the "offline" voltage.

I am not sure about your 500mA constant current load, but it most likely reads the voltage while pulling current. This requires the "four point" method to avoid contact and wire IR loss (2 for current, 2 for voltage).

Such voltage is called the "online voltage."

Online voltage, during discharging, is always lower than offline voltage. So if you terminated at 1.00V using online voltage, the capacity will be less than the MH-C9000.

Hope this helps!

William
 

Curious_character

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willchueh said:
Curious_character,

While it is not a instrument, the MH-C9000 can provide discharge current at 1-2% within set value.

As indicated in my earlier post, the MH-C9000 uses a two-point method for charging and voltage measurement. Therefore, to avoid contact resistance loss, the charger needs to pause the current and measure the voltage (also to eliminates noise from high current).

We call this the "offline" voltage.

I am not sure about your 500mA constant current load, but it most likely reads the voltage while pulling current. This requires the "four point" method to avoid contact and wire IR loss (2 for current, 2 for voltage).

Such voltage is called the "online voltage."

Online voltage, during discharging, is always lower than offline voltage. So if you terminated at 1.00V using online voltage, the capacity will be less than the MH-C9000.

Hope this helps!

William
William,

Thanks, I understand that. Yes, my tester measures the voltage while drawing current. A flashlight or other device, after all, doesn't periodically disconnect itself to measure voltage -- the light dims according to the "online voltage". Also, all battery specification sheets I've seen recommend termination at 1.0 "online" volts, and specify capacity to 1.0 "online" volts. So while interesting, it's not apparent to me what the tester accomplishes by using the "offline voltage" to determine capacity and terminate the discharge, since this neither imitates manufacturers' test procedures nor actual usage. Four point measurement isn't really necessary at the modest current levels involved, unless the contacts and/or conductors to the cells are extraordinarily resistive or if extremely high precision voltage measurements are necessary. I don't think either is the case here, but maybe the tester's battery contacts are poorer than I'm assuming.

I'd like to see a real constant current discharge, terminated at a fixed "online" voltage. The reason is that it would enable me to spot high resistance cells. They'd show low capacity at high current discharge but normal capacity at low current discharge. I don't know of any systematic way to spot these cells with the tester as it is, other than comparing the tester's reported capacity with the capacity I see in real constant-current tests.

A related but different issue is the discharge current. My C9000 indicates a
dropping current near the end of the discharge. In a previous posting I thought you said that this is normal for the tester because it's unable to regulate current below about 0.9 volt ("online" voltage). Did I misinterpret what you said?

I'd like to make a correction to my earlier posting, where I said that for cells like the ones I have with high resistance, the Maha-reported capacity would be reasonably accurate for an unregulated light. I was thinking only of LED flashlights, where the current drops dramatically with voltage. Incandescent bulbs present a fairly constant current load, so the Maha-reported capacity wouldn't be realized in incandescent lights if the cells have a high internal resistance.

c_c
 
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